Social network services, such as, for example, Facebook, Twitter and LinkedIn, allow for social interactions between their users. Typically, a social network service comprises a representation of each user, which is often configured as a profile including personal details of the user, and it includes the social links between the users. The social links often comprise “friendship” relations or the like, which are established after a confirmation of the users linked to each other.
In addition, social network services allow users to engage in social activities, such as, for example, posting or publishing content for other users of the social network service, sharing existing content with other users and commenting on content published by other users. By means of such activities, social network services allow for a social interaction between its users beyond the provision of personal details of the users.
Usually, social network services of the aforementioned type are provided at social network sites, which are accessed through the Internet or another network. The social network sites are operated by a service provider, which also stores the data of the users of the social network service. Due to the centralized architecture it is required to register with the service provider in order to join a social network service. Furthermore, the social interactions are restricted to one social network site.
If a user whishes to participate in more than one social network service, he may register with each social network site. However, user data and social interactions in one social network site cannot be transferred to another social network site. Thus, a user has to provide his data in each social network site and he has to perform social interactions in each social network site separately. This is very cumbersome for the user.